Symptomatic versus asymptomatic papillary thyroid microcarcinoma: a retrospective analysis of surgical outcome and prognostic factors.

Although the mortality rate associated with papillary microcarcinoma (PMC) of the thyroid generally is very low, some patients present with bulky nodal metastasis or distant metastasis and have an unfavorable prognosis. We retrospectively reviewed clinical aspects, surgical treatment and outcome of 178 patients with PMC in an attempt to determine the prognostic factors. The cause-specific 10-year survival rate was 96%. Three of four patients who showed signs of distant metastasis during the postsurgical period died of the disease, and another died of local recurrence. The most significant prognostic factors were the presence of clinically apparent lymph-node metastasis and hoarseness due to recurrent nerve palsy at the time of diagnosis. All distant metastases and cancer-specific deaths occurred in the 30 patients with symptomatic PMC who had either cervical lymphadenopathy, recurrent laryngeal nerve palsy or both. The 148 patients who had neither symptom had a distinctly favorable outcome. Total thyroidectomy followed by radioactive iodine treatment did not improve the final outcome in patients with symptomatic PMC. We conclude that patients with asymptomatic PMC can expect a truly favorable outcome, but some of those with symptomatic PMC may fall within a high-risk group of patients who do not benefit from aggressive treatment.